Synergistic Effect of Photocatalyst CdS and Thermalcatalyst Cr2O3-Al2O3 for Selective Oxidation of Aromatic Alcohols into Corresponding Aldehydes

Synthesis of Titania nanowires doped with Cd on the based Polycalix[4]resorcinarene for photocatalytic oxidation of aromatic alcohols under LED irradiation

Semiconductor photocatalysis as an alternative technology has received extensive attention for addressing worldwide energy and environmental issues. However, it is still a great challenge and imperative to profoundly understand the migration mechanisms for achieving the complete utilization of photoexcited charge carriers. Photocatalytic selective oxidation of alcohols into corresponding aldehydes has received enormous attention. In this paper, The structure of the TiO2NWs-Cd/Polycalix[4]resorcinarene nanocomposites was analyzed by thermal sonicate and solvothermal methods and then thoroughly characterized by a range of XRD, FT-IR, SEM, PL, and DRS techniques. The photoactivity of the compounds against the oxidation of four substituted benzyl alcohols was surveyed. The resultant nanocomposite (TiO2NWs-Cd(48%)/Polycalix[4]resorcinarene) demonstrates greater photocatalytic efficiency than both its pure TiO2 and cadmium-doped TiO2 for the oxidation of benzyl alcohols under the illumination of LED light (λ ≥ 400 nm). The introduction of the TiO2NWs-Cd on the surface of Polycalix[4]resorcinarene can improve the absorption ability in the visible region and the separation efficiency of charge carriers during photocatalytic oxidation. Hence, these obtained results show that the TiO2NWs-Cd (48wt%)/Polycalix[4]resorcinarene nanocomposite possesses high photocatalytic performance and excellent reusability in oxidation reactions and LED-light-driven organic oxidations carried out under mild conditions offering a sustainable approach to performing chemical transformations important to the chemical industry.

Fabrication of core-shell Prussian blue analogue@ZnIn2S4 nanocubes for efficient photocatalytic hydrogen evolution coupled with biomass furfuryl alcohol oxidation

Utilizing photocatalytic technology for the value-added conversion of biomass derivatives, alongside the production of clean hydrogen energy, represents a viable approach to addressing energy and environmental challenges. However, the design of cost-effective and efficient photocatalysts remains a significant obstacle. In this work, we employed open-framework Prussian blue analogs as co-catalytic centers and combined them with ZnIn2S4 to construct a series of core-shell nanocube photocatalysts with varying metal compositions. This unique structure provides abundant photocatalytic redox-active sites and effectively facilitates the separation and transfer of photoinduced charges. By examining the oxidation of furfuryl alcohol (FOL) to furfural (FAL) with cooperative H2 evolution, the optimal Ni-Co PBA@ZnIn2S4 sample exhibited remarkable catalytic activity, achieving H2 and FAL yields of 739.3 and 705.2 μmol g-1 h-1, respectively, which is approximately four times greater than that achieved with bare ZnIn2S4. This study offers valuable insights into the design of photocatalysts and the selection of co-catalytic metal centers.

Photothermal Catalytic Degradation of VOCs: Mode, System and Application

Human production and living processes emit excessive VOCs into the atmosphere, posing significant threats to both human health and the environment. The photothermal catalytic oxidation process is an organic combination of photocatalysis and thermocatalysis. Utilizing photothermal catalytic degradation of VOCs can achieve better catalytic activity at lower temperatures, resulting in more rapid and thorough degradation of these compounds. Photothermal catalysis has been increasingly applied in the treatment of atmospheric VOCs due to its many advantages. A brief introduction on the three modes of photothermal catalysis is presented. Depending on the main driving force of the reactions, they can be categorized into thermal-assisted photocatalysis (TAPC), photo-assisted thermal catalysis (PATC) and photo-driven thermal catalysis (PDTC). The commonly used catalyst design methods and reactor types for photothermal catalysis are also briefly introduced. This paper then focuses on recent developments in specific applications for photothermal catalytic oxidation of different types of VOCs and their corresponding principles. Finally, the problems and challenges facing VOC degradation through this method are summarized, along with prospects for future research.

New insight into highly efficient CSA@g-C3N4 for photocatalytic oxidation of benzyl alcohol and thioanisole: NAEDS as a promoter of photoactivity under blue LED irradiation

An open new perspective has been established toward synthesizing eco-friendly CSA@g-C3N4 employing surface engineering. The carbon nitride modified through camphorsulfonic acid was designed and developed in a category of the new generation of photocatalysts for the oxidation of benzyl alcohol and thioanisole in the existence of a natural deep eutectic solvent (NADES). In comparison with pure g-C3N4, not only does CSA@g-C3N4 exhibit an extraordinarily higher ability for harvesting visible light stemming from declining the recombination rate of electrons/holes dependent on PL results but it also reveals notable photocatalytic oxidation capability in the transformation of alcohols as well as thiols into relevant compounds. In addition, non-metal compound (CSA) incorporation would result in considerably diminishing the energy band gap value from 2.8 to 2.28 eV to escalate the visible-light absorption of g-C3N4. While the conventional consensus implies that inherent properties of photocatalysts bring on high photoactivity, this study indicates that deploying choline chloride-urea deep eutectic solvent as an external factor plays the role of photoactivity accelerator. Furthermore, readily recycling and reusability can be achieved for the photocatalytic setup of CSA@g-C3N4 ascribed to its heterogeneous nature with no drop in the photoactivity.

A binary dumbbell visible light driven photocatalyst for simultaneous hydrogen production with the selective oxidation of benzyl alcohol to benzaldehyde

Photocatalytic H2 production with selective oxidation of organic moieties in an aqueous medium is a fascinating research area. However, the rational design of photocatalysts and their photocatalytic performance are still inadequate. In this work, we efficiently synthesized the MoS2 tipped CdS nanowires (NWs) photocatalyst using soft templates via the two-step hydrothermal method for efficient H2 production with selective oxidation of benzyl alcohol (BO) under visible light illumination. The optimized MoS2 tipped CdS NWs (20 % MoS2) photocatalyst exhibits the highest photocatalytic H2 production efficiency of 13.55 mmol g-1 h-1 with 99 % selective oxidation of BO, which was 42.34 and 2.21 times greater photocatalytic performance than that of pristine CdS NWs and MoS2/CdS NWs, respectively. The directional loading of MoS2 at the tips of CdS NWs (as compared to nondirectional MoS2 at CdS NWs) is the key factor towards superior H2 production with 99 % selective oxidation of BO and has an inhibitory effect on the photo corrosion of pristine CdS NWs. Therefore, the amazing enhancement in the photocatalytic performance and selectivity of optimized MoS2 tipped CdS NWs (20 % MoS2) photocatalyst is due to the spatial separation of their photoexcited charge carriers through the Schottky junction. Moreover, the unique structure of the MoS2 flower at the tip of 1D CdS NWs offers separate active sites for adsorption and surface reactions such as H2 production at the MoS2 flower (confirmed by Pt photo deposition) and subsequently the selective oxidation of BO at the stem of CdS NWs. This rational design of a photocatalyst could be an inspiring work for the further development of an efficient photocatalytic system for H2 production with selective oxidation of BO (a strategy of mashing two potatoes with one fork).

The Mars-Van Krevelen cycle and non-noble metal Ni jointly promoting Z-scheme charge transfer: a study on the photothermal synergy effect applied in selectively oxidizing aromatic alcohols

Photothermal catalysis is a promising method for selectively oxidizing organic compounds, effectively addressing the energy-intensive and low-selective processes of thermal catalysis, as well as the slow reaction rates of photocatalysis. In this study, a ternary photothermal catalyst, Ni/CeO2/CdS, was synthesized using a simple calcination and solvothermal method. The catalyst demonstrated remarkable improvement in reaction rates and achieved nearly 100% selectivity in converting benzyl alcohol to benzaldehyde through photothermal catalysis at normal pressure. The reaction rates were 5.9 times and 63 times higher than those of CdS and Ni/CeO2 individually. XPS analysis confirmed that the thermal catalysis followed the Mars-Van Krevelen (MVK) mechanism and also proved that photocatalysis facilitated the MVK cycle. Additionally, DFT calculations showed that Ni acted as an electron transfer channel, facilitating efficient Z-scheme charge transfer. The in situ infrared technique was used to dynamically monitor the reaction process and explain the high selectivity of the product. Furthermore, detailed explanations of photocatalysis, thermocatalysis, and photothermal synergistic catalysis were proposed based on the aforementioned characterization and theoretical calculations. This approach establishes a theoretical foundation for the development of efficient photothermal catalysts.

Carbazole-Involved Conjugated Microporous Polymer Hollow Spheres for Selective Photocatalytic Oxidation of Benzyl Alcohol under Visible-Light Irradiation

Conjugated microporous polymers (CMPs) have been considered a type of promising visible-light-driven, organic photocatalysts. However, apart from designing high-performance CMPs from a molecular perspective, little attention is paid to improving the photocatalytic properties of these polymers through macrostructural regulation. Herein, we prepared a kind of hollow spherical CMPs involving carbazole monomers and studied their performance on the selective photocatalytic oxidation of benzyl alcohol under visible light irradiation. The results demonstrate that the introduction of a hollow spherical structure improves the physicochemical properties of the as-designed CMPs, including the specific surface areas, optoelectronic characteristics, as well as photocatalytic performance, etc. In particular, the hollow CMPs can more effectively oxidize benzyl alcohol compared to pristine ones under blue light illumination, and produce >1 mmol of benzaldehyde in 4.5 h with a yield of up to 9 mmol·g^-1·h^-1, which is almost 5 times higher than that of the pristine ones. Furthermore, such hollow architecture has a similar enhanced effect on the oxidation of some other aromatic alcohols. This work shows that the deliberate construction of specific macrostructures can better arouse the photocatalytic activity of the as-designed CMPs, which will contribute to the further use of these organic polymer semiconductors in photocatalysis areas.

Pine Dendritic Bi/BiOBr Photocatalyst for Efficient Degradation of Antibiotics

Constructing Bi/BiOX (X = Cl, Br) heterostructures with unique electron transfer channels enables charge carriers to transfer unidirectionally at the metal/semiconductor junction and inhibits the backflow of photogenerated carriers. Herein, novel pine dendritic Bi/BiOX (X = Cl, Br) nanoassemblies with multiple electron transfer channels have been successfully synthesized with the assistance of l-cysteine (l-Cys) through a one-step solvothermal method. Such a pine dendritic Bi/BiOBr photocatalyst shows excellent activity toward the degradation of many antibiotics such as tetracycline (TC), norfloxacin, and ciprofloxacin. In particular, its photocatalytic degradation activity of TC is higher than those of reference spherical Bi/BiOBr, lamellar BiOBr, and BiOBr/Bi/BiOBr double-sided nanosheet arrays. Comprehensive characterizations demonstrate that the pine dendritic structure can construct multiple electron transfer channels from BiOBr to metallic Bi, resulting in an obviously promoted separation efficiency of photogenerated carriers. The synthesis method that uses l-Cys to control the morphology provides a guidance to prepare special metal/semiconductor photocatalysts and would be helpful to design a highly efficient photocatalytic process.

Solvent-less Oxidation of Aromatic Alcohols Using CrO3/Al2O3 under Ultrasonic Irradiation

Alcohol oxidation plays an essential contribution to the chemical industry. Innovative green techniques, such as ultrasound irradiation, could be economically remarkable by enhancing reaction yield. In this research, the design and improvement of a new green ultrasound-assisted oxidation of alcohols procedure using CrO3 supported by Al2O3 with the addition of a small amount of t- butanol were reported. The oxidation of alcohols was also done without ultrasound irradiation to study the sonochemical effect. Based on FTIR and GC/MS analyses, the alcohols were effectively oxidized into their corresponding aldehydes in satisfactory yields (74–93%). The yield of the obtained aldehydes was increased by applying the ultrasonic irradiation technique, and no over-oxidation products were found. Overall, the innovative procedure offers several benefits, such as being easy to use, environmentally friendly, capable of improving yields, and having shorter oxidation times.

One-step conversion of lignin-derived alkylphenols to light arenes by co-breaking of C–O and C–C bonds

The selectivity for light arenes, including benzene and toluene, in the conversion of 4-ethylphenol reaches 55.7% with 84.0% selectivity for arenes.

Efficient H2 evolution on Co3S4/Zn0.5Cd0.5S nanocomposite by photocatalytic synergistic reaction

To achieve high photocatalytic efficiency of H2 evolution, promoting the utilization rate of photogenerated charge carriers by photocatalytic synergistic reaction is an efficient strategy. In this work, Co3S4/Zn0.5Cd0.5S nanocomposites with...